1. Field of the Invention
This invention relates to lettering elements, including figures and designs, cut from pigmented flexible plastic sheet material; and to the process of applying them in an aligned group, as on fabrics, commercial awnings and other surfaces.
2. Description of Related Art
U.S. Pat. No. 3,660,212 to Liebe discloses a process for making plastic lettering material comprising a paper release sheet, a vinyl display layer, and an encapsulating thermoplastic adhesive sheet bonded to the surface of the display layer opposite the release sheet. For application of a design or lettering onto a woven or knitted garment or other permanent substrate, separate lettering elements are die-stamped from such sheet material and individually positioned and heat bonded (in effect ironed) onto the surface of the substrate, the heat liquified adhesive creating a mechanical bond by flowing into and curing within the interstitial spaces of the porous surface of the substrate. Such lettering material is serviceable but requires careful and time-consuming alignment of the separate lettering elements upon application to the chosen substrate.
Other transfer sheet materials of the prior art provide a release sheet which remains whole and uncut throughout the application process, but require that designs or lettering elements be either cut separately and applied to the release sheet, or printed on the release sheet prior to application to the substrate. Thus, for each desired design, an unique transfer sheet must be put together; design elements must be applied to the release sheet in the desired alignment and adhesive must then be applied over the design material. Such requirements make it impossible to use a transfer sheet material which has release sheet, display layer and adhesive layer already fabricated together into a unitary composite sheet.
Yet other transfer sheet materials which are suitable for use in thermal printers incorporate release sheets bonded to continuous ink and adhesive layers forming a unitary composite sheet, but to permit the rapid heat transfer required for successful use with a thermal printer, the composite sheets must be so thin that transfer of lettering elements of the size and durability necessary for clothing, signs and larger displays is not practical.
For the foregoing reasons, there is a need for a transfer sheet material which can be supplied as a unitary composite sheet in pre-laminated form and from which a plurality of large and durable lettering elements may be cut and subsequently transferred to a chosen substrate in the same alignment as they were cut into the transfer sheet material.